Green commons, if we stick to r/g ramp.

Elvish Warrior
Elvish Visionary
Primal Huntbeast
Elvish Aberration
Oakgnarl Warrior
Walker of the Grove

Seething Song
Macetail Hystrodon as red ramp commons.
RG in general needs more high cost stuff.

Yes to all of this. I'm still sort of flirting with a dying matters/sacrifice/counters thing in , so that might work if cares about counters, too. I'll try and come up with suggestions for that next time. For now, here are some miscellaneous suggestions to fill a few gaps in general (okay, most of them are wolves to support my little fringe synergy):

Mtenda Lion (Look how thirsty it is!)
Ember-Eye Wolf (Amazing artwork, might feel at home in , and )
Krark-Clan Grunt (I think I already suggested this earlier)
Assembled Alphas (Impressive name, works in ramp)
Howlgeist (Could work in both Death Counters and Growing Counters if any of this becomes a thing)
Lone Wolf
Pyreheart Wolf (another wolf with cool artwork, and giving all your stuff Menace sounds great for , and )
Scourge Wolf (Amazing flavour and artwork, might feel at home in and even more so in if enough of the discard stuff stays in)
Somberwald Alpha (Giving creatures trample might be an option for ramp or just any green deck that packs creatures with counters)
Vastwood Hydra (Seems to fit into pretty much every archetype one way or another)

It's probably a good idea to decide on the non-basic lands at the end when everything else is done, but here are a few flavourful suggestions that we could come back to:

Volrath's Stronghold
Phyrexian Tower
Academy Ruins
Tolarian Academy
Gaea's Cradle
Serra's Sanctum
Oran-Rief, the Vastwood (fun with all those green tokens)
Vitu-Ghazi, the City-Tree
Sunhome, Fortress of the Legion
Llanowar Reborn
Buried Ruin
Great Furnace
Seat of the Synod
Darksteel Citadel (Maybe)
Westvale Abbey
Geier Reach Sanitarium

(I'll update the list later, need to get some actual work done first.)
I like a lot of those Wolves. The artwork on Wolves seems to be pretty darn good in general. A shame there aren't more Wolves in colors outside of Red and Green.

As for the non-basic lands, my original idea was to rarity-shift some dual-lands down because (a) I think it's stupid that good dual-lands are always rare and (b) it helps with colorfixing. Tevish mentioned that it might be a good/fun idea to make allied-color lands better than enemy colored and I still like that idea. An alternative that just popped into my head was to have only dual-lands for allied colors, which would free up 5 slots for random cool lands. Balance-wise this might not be the greatest idea, though.

For both the +1/+1 theme and the control decks, Aether Figment might be fun and I've always loved that art. (I should make a deck with it.)

Corrupted Conscience shows an important moment in the story and gives us both the generic "I steal your stuff" card and another tool for Blue-Black and Blue-Green. I also want an infect creature in Green if we go down this road, but I don't find any of them particularly flavorful. There is a Wolf with infect, though. Not particularly interesting from a Vorthos perspective, unfortunately.

I also like Primal Cocoon event though it's a worse Forced Adaptation. The art is better and I think the marriage of mechanics and concept just works a lot better with the cocoon.

In general, more quests might help multiple themes while also being great for anything that cares about enchantments and counters. And they're generally reasonably flavorful by default. And they are amazingly fun to play with, in my experience.

(a) I think it's stupid that good dual-lands are always rare and (b) it helps with colorfixing

My thoughts exactly.

Ah, fair enough, I had forgotten about the dual lands. Huh, yeah, Aether Figment looks really cool. Seems like someone finally gave Thomas M. Baxa new colours for Christmas. Also, I'm a twerp, I completely overlooked the second page full of wolves in Gatherer...

Tundra Wolves is a thing, for what it's worth. I like the old artwork better, though, the new one looks pretty monstrous.
Wandering Wolf might get interesting if you put enough counters on it.
Wolf of Devil's Breach is pretty badass and has flavour text by Arlinn Kord. Could be useful in because you have high cmc to disacrd and in , especially if some of the Madness stuff etc. stays in.
Wolf Pack also works with counters and/or ramp. Or just as a finisher in general. I find it hilarious that Lone Wolf and Wolf Pack have the same ability, though.
Wolfir Silverheart is generally awesome, and giving the poor, neglected Wolfir some love would be nice.
Young Wolf is cute and would fit perectly into the theme I was talking about.

Again, I'm not trying to clutter everything up with as many wolves as possible at the expense of other cool cards. Just use them where it fits organically and try to make it worthwhile to commit to some wolf tribal if you still like the idea.

Other cool stuff:

Fyndhorn Elder (preferably Sixth Edition)
Ring of Three Wishes
Alluring Siren
Perhaps one or two small dragons, like Dragon Whelp, Furnace Whelp or Dragon Hatchling.
Dragon Egg, Roc Egg or Rukh Egg could also go in there. Man, it really sucks that Egg isn't a creature type anymore. Lame pun intended. I also really like Bird Maiden, but that's probably redundant if you go with the small dragons instead.

Edit: Speaking of dragons, I might as well throw good old Shivan Dragon into the ring. Oh, and speaking of rings, the Shandalar rings might help out the counter theme a little bit while also being pretty flavourful. You know, Ring of Kalonia and consorts.

@Green Infect: I think Glistener Elf is a good spotlight for the corruption of the Mirrans. I mean, it's no Lost Leonin, but the existence of such traitors is a kind of cool touch. Plaguemaw Beast isn't super-flavorful, but if we're hole filling it REALLY supports counter themes (not infect-y though I admit)

For Cocoons, there's always Cocoon. I mean, it's terrible, but it's a flavor home-run to turn your critter into a beautiful butterfly.

I feel like Clockspinning and Power Conduit could be great supports.

For duals, I feel like the Future Sight 5 (Nimbus Maze, River of Tears, Graven Cairns, Grove of the Burnwillows, Horizon Canopy) would be great, but Allied Pains plus Tempest enemey Enters-Tapped-Pains would also work. I really support the Enters-Tapped-Pains for enemy color duals (Skyshroud Forest and its ilk) but I think I've said that before. Perhaps they could go with the Tempest allied duals (Rootwater Depths) to make the duals feel cycle-y?

I recall a while ago there was a discussion of Crux of Fate needing some dragons? How about the Primevals (Treva, the Renewer) at M or R and the Elders (Arcades Sabboth) at the other?

Glistener Elf would probably be fine if there really is space for Infect. Having a few elves around is good, too, because it might enable us to include Wren's Run Packmaster. Alternatively, we could consider Viridian Corrupter, which has the advantage of being somewhat more useful in your deck if you don't commit to Infect. Viridian Betrayers is a flavourful representation of, well, betrayers. But I guess it doesn't fill the slot you're looking for because you need Infect to give it Infect in the first place. Blightwidow at least works as a scary blocker when you don't play Infect.

The Future Sight lands are cool.

The Primevals are probably splashable, but the Elder Dragons might be a bit too over the top unwieldy in this Limited environment. I mean, it looks like it's going to be rather slow for the most part, but a whole cycle of three-colour eight mana creatures with upkeep cost etc. sounds like it could be too much. Maybe we could just include Nicol Bolas?

I sweeped card database for cool green and red commons.
If you dislike them for some reason, say it to me, please.
I'd like to cooperate!

Some mispeelings in the OP are here:
Sould Manipulation
Skyclaw Trash
Campain of Vengeance
Fires of Yavimaya and Frenzied Tilling have something going on with the tags.
As do savage ventmaw and sleeper's robe
Tilsimir Wolfblood
Fabel Of Wolf and Owl has Wolf and Owl switched.

I'm stil in favour of a double suicide BR archetype. Flayer of the hatebound asks, why do a Macabre Waltz when you can do the Cauldron Dance?

Also, Kazuul, Tyrant of the Cliffs needs to show up.

I don't think we need to list basic lands either.

Sorry if I gave you the impression of ignoring you. My brain just isn't working properly for months now, which isn't much of an excuse. I like the effort you're bringing to this and pretty much all of those cards are great.

@TP: Thanks for the spellcheck. I'll update it as soon as I can focus on one thing for more than 10 seconds.

So... What UG will do ? Proliferation and counters ?

Cut suggestions and mechanical demand:

G Rares
Autumn Willow
Feed the pack
Skinshifter
Demand for 3-2 UG counters cards, and 1-2 BG graveyard cards.

R Rares
Hoarding Dranon OR Bludgeon Brawl (super cool card, but four cards care about artifacts, and that's not cool.)
Ashling the Piligrim
Magus of the Scroll
Demand for 3-2 RG ramp cards.

B Rares
4 of the following: [Sleeper Agent, Triskadekaphobia, Phage the Untouchable, Maralen of the Moors, Magus of the Will, Anowon, The Ruin Sage]
Damn, I wish we won't care about rarity ! Maybe we stop that right now, eh ? We should cut so flavorful stuff for such a stupid reason...
Gibbering Descent OR Asylum Visitor, where Visitor is better mechanically, and Descent is just awesomer.
Demand for 2-1 BG life gain support.

U Rares
Ugin's Insight
Teferi, Mage of Zhaltir OR Stitcher Geralf
Meditate (Arcanis, Bident and Suspicions still draw cards, and IMHO cooler then Insight and Meditate, while also fitting in archetypes)
Demand for 2-1 UG +1/+1 counter stuff, and 0-1 UW defensive enchantment.

W Rares
2 of the following: Konda, Cho-Manno, Hundred-Handed One. (We added 3 copies of almost the same card !)
Chained to the Rocks isn't really white - it's WR multicolored. So either Chained or Figure of Destiny.
Demand for 2-1 BG life gain stuff, 3-2 GW go wide stuff, 0-1 combat trick.

Uncommons and commons will follow.

I realise we should probably start making cuts rather than suggest more and more cards, but I had an epiphany: What about Hangarback Walker?

It has an artifact theme. A counter theme. A token theme. It plays well with ramp. It has a death trigger. It could work as a finisher for control.
And it's a walking hangar that makes thopters, so I guess it qualifies as flavourful.


Oh, and while I'm at it, Reyhan, Last of the Abzan would fit into Death Counters if that works out as that archetype.

We need to finish this one.

Most definitely.